Known in the art is a crystal unit having a crystal element and a temperature sensor (for example Patent Literature 1). The crystal element has for example a crystal blank and a pair of excitation electrodes provided on a pair of major surfaces of the crystal blank. This is excited by application of voltage and is utilized for generation of an oscillation signal having a constant frequency. Further, the detection value of the temperature sensor is for example utilized for a temperature compensation circuit which compensates for a change of characteristic of the crystal element due to a temperature change. The crystal blank in Patent Literature 1 is formed by a beveling or other machining.